1. Field of the Invention
The invention relates to a tissue punch, and more particularly, the invention relates to a tissue punch for forming an opening in a target blood vessel for deploying an anastomosis device to connect a graft vessel to the target blood vessel.
2. Brief Description of the Related Art
Vascular anastomosis is a procedure by which two blood vessels within a patient are surgically joined together. Vascular anastomosis is performed during treatment of a variety of conditions including coronary artery disease, diseases of the great and peripheral vessels, organ transplantation, and trauma. In coronary artery disease (CAD) an occlusion or stenosis in a coronary artery interferes with blood flow to the heart muscle. Treatment of CAD involves the grafting of a vessel in the form of a prosthesis or harvested artery or vein to reroute blood flow around the occlusion and restore adequate blood flow to the heart muscle. This treatment is known as coronary artery bypass grafting (CABG).
In the conventional CABG, a large incision is made in the chest and the sternum is sawed in half to allow access to the heart. In addition, a heart lung machine is used to circulate the patients blood so that the heart can be stopped and the anastomosis can be performed. During this procedure, the aorta is clamped which can lead to trauma of the aortic tissue and/or dislodge plaque emboli, both of which increase the likelihood of neurological complications. In order to minimize the trauma to the patient induced by conventional CABG, less invasive techniques have been developed in which the surgery is performed through small incisions in the patients chest with the aid of visualizing scopes. Less invasive CABG can be performed on a beating or stopped heart and thus may avoid the need for cardiopulmonary bypass.
In both conventional and less invasive CABG procedures, the surgeon has to suture one end of the graft vessel to the coronary artery and the other end of the graft vessel to a blood supplying vein or artery. The suturing process is a time consuming and difficult procedure requiring a high level of surgical skill. In order to perform the suturing of the graft to the coronary artery and the blood supplying artery the surgeon must have relatively unobstructed access to the anastomosis site within the patient. In the less invasive surgical approaches, some of the major coronary arteries including the ascending aorta cannot be easily reached by the surgeon because of their location. This makes suturing either difficult or impossible for some coronary artery sites. In addition, some target vessels, such as heavily calcified coronary vessels, vessels having very small diameter, and previously bypassed vessels may make the suturing process difficult or impossible.
Accordingly, it would be desirable to provide a sutureless vascular anastomosis device which easily connects a graft vessel to a target vessel and can be deployed in limited space.
Deployment of a sutureless anastomosis device, such as those described in U.S. patent application Ser. No. 09/314,278, involves forming an opening in the target vessel and inserting the anastomosis device with a graft vessel attached into the opening. Accordingly, it would be desirable to provide a one piece tool which can perform both tissue punching and anastomosis device deployment. In order to provide a one piece device it would be desirable to provide a tissue punch which is advanced through a trocar and then is moved out of the trocar to allow deployment of the anastomosis device through the same trocar.
The present invention relates to a tissue punch for forming an opening in a target blood vessel for deploying an anastomosis device to connect a graft vessel to the target vessel.
In accordance with one aspect of the present invention, an apparatus for piercing a vessel, punching a hole in the vessel, removing punched tissue from the vessel, and introducing an object into the vessel through the punched hole is described. The apparatus includes a punch with a pointed piercing end for piercing a vessel to allow introduction of the punch into the vessel, a tubular element arranged coaxially with the punch through which the punch retracts to remove vessel tissue, and an introducer located coaxially around the tubular element. The introducer includes an area into which the punch and tubular element can be moved to allow introduction of an object into the punched hole in the vessel through the introducer.
In accordance with another aspect of the present invention, a tissue punch includes a piercing element, a cutting edge, and a trocar receiving the piercing element. The piercing element has a pointed distal end, a tissue receiving space, and an anvil adjacent the tissue receiving space. The cutting edge is arranged to contact the anvil to cut a piece of tissue. The trocar has a side opening for removing the piercing element from the trocar after punching tissue.
In accordance with an additional aspect of the present invention, a method of punching a plug of tissue from the wall of a blood vessel includes the steps of penetrating the wall of the blood vessel with a piercing element to form an opening in the blood vessel, punching a plug of tissue around the opening in the blood vessel, and inserting a trocar into the punched hole in the blood vessel.
In accordance with a further aspect of the invention, a double tissue punch includes a piercing element having a pointed distal end and a first anvil surface; a first cutting element movable with respect to the piercing element, the first cutting element having a cutting edge arranged to contact the first anvil surface; and the first cutting element having a second anvil surface, a second cutting element movable with respect to the piercing element and the first cutting element, the second cutting element having a cutting edge arranged to contact the second anvil surface.
The present invention provides advantages of a tissue punch which is deployed through a trocar and is removed through a side wall of the trocar so that the trocar can subsequently be used for deployment of a medical device. The invention also provides the advantage of trapping a tissue plug which is cut by the tissue punch.